Terminal and radio communication method

Abstract

This terminal transmits a random access preamble on the basis of a command by a downlink control channel. When in a candidate cell of a transition destination by terminal-initiated mobility control by a lower layer, the terminal acquires a timing adjustment value to be applied to the candidate cell according to the command, and starts a timer for measuring a validity period of the timing adjustment value.

Description

Terminal and wireless communication method

[0001] The present disclosure relates to a terminal and a wireless communication method that supports LTM (L1 / L2 mobility).

[0002] The 3rd Generation Partnership Project (3GPP: registered trademark) is developing specifications for the 5th generation mobile communication system (5G, also known as New Radio (NR) or Next Generation (NG)), and is also developing specifications for the next generation, known as Beyond 5G, 5G Evolution, or 6G.

[0003] For example, 3GPP Release 19 discusses extensions to Layer 1 / Layer 2 mobility (L1 / L2 mobility, specifically, Lower Layer Triggered Mobility (LTM)) (see Non-Patent Document 1). LTM is a technology related to the mobility of a terminal (User Equipment, UE) in Layer 1 or Layer 2, and includes the transition of a UE to another cell (handover (HO)). HO using LTM is realized by a lower layer such as the Medium Access Control layer (MAC).

[0004] In addition, in Conditional LTM, specifically UE-triggered LTM, like conditional handover (CHO), the UE receives a specific execution condition from the radio base station (gNB), monitors the status according to the execution condition, and executes handover to another cell if the execution condition is satisfied. Furthermore, LTM enables HO without a random access procedure (RA procedure) (RACH less HO).

[0005] In the case of RACH less HO, a random access response (RAR) from the gNB to the UE is omitted, so the UE cannot know the timing advance (TA) to be applied in the target cell. Therefore, a method (early TA acquisition) has been specified in which the target cell (which may also be called a target gNB, candidate cell, etc.) acquires a TA for its own cell in advance (Non-Patent Document 2). The TA acquired by the target cell through early TA acquisition is notified to the UE by a Cell Switch Command MAC-CE. In early TA acquisition, early synchronization specified in 3GPP TS38.300 may be performed.

[0006] In the case of LTM, a random access channel (PRACH: Physical Random Access Channel) is specified as a PDCCH ordered RACH without RAR, which transmits a random access preamble in response to a command from a PDCCH (Physical Downlink Control Channel) and can omit the RAR (Non-Patent Document 3). Also, 3GPP Release 19 is considering a PDCCH ordered RACH with RAR, in which the RAR is transmitted from the target cell without omitting the RAR.

[0007] The UE can obtain the TA by the PDCCH ordered RACH described above, or can obtain the TA by the UE directly measuring the TA (which may be referred to as UE-based TA measurement).

[0008] "New WID: NR mobility enhancements Phase 4", RP-234036, 3GPP TSG RAN Meeting #102, 3GPP, December 20233GPP TS 38.401 V18.0.0, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NG-RAN; Architecture description (Release 18), 3GPP, December 2023 3GPP TS 38.300 V18.1.0, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; NR and NG-RAN Overall Description; Stage 2 (Release 18), 3GPP, March 2024

[0009] Even when early TA acquisition is performed in Conditional LTM, TA can be acquired by UE-based TA measurement or PDCCH-ordered RACH (PDCCH-ordered RACH without RAR, PDCCH-ordered RACH with RAR).

[0010] However, when TA is acquired by PDCCH-ordered RACH, it may take time for the execution condition to be satisfied, and the acquired TA may become invalid. Furthermore, when TA is acquired by PDCCH-ordered RACH, the UE needs to manage the acquired TA, which may cause confusion if there is no clear instruction from the network.

[0011] Therefore, the following disclosure has been made in consideration of this situation, and aims to provide a terminal and a wireless communication method that can operate appropriately using the acquired TA even when early TA acquisition is performed in Conditional LTM.

[0012] One aspect of the present disclosure is a terminal (UE200) that includes a transmitter (RA execution unit 220) that transmits a random access preamble based on an instruction via a downlink control channel, and a control unit (control unit 240) that, in a candidate cell to which a transition is to be made based on terminal-driven mobility control via a lower layer, obtains a timing adjustment value to be applied to the candidate cell based on the instruction, and starts a timer that measures the validity period of the timing adjustment value.

[0013] FIG. 1 is a diagram illustrating an overall schematic configuration of a wireless communication system 10. FIG. 2 is a diagram illustrating an example of control using LTM (L1 / L2 mobility). FIG. 3 is a functional block diagram of a gNB 100. FIG. 4 is a functional block diagram of a UE 200. FIG. 5 is a diagram illustrating an example of a RACH sequence according to PDCCH ordered RACH without RAR. FIG. 6 is a diagram illustrating an example of a RACH sequence according to PDCCH ordered RACH with RAR. FIG. 7 is an explanatory diagram illustrating the relationship between satisfaction of an execution condition in Conditional LTM and an LTM cell switch. FIG. 8 is a diagram illustrating an example of application of a timeAlignmentTimer according to an operation example. FIG. 9 is a diagram illustrating an example of a transmission sequence of UE Capability Information. FIG. 10 is a diagram illustrating an example of the hardware configuration of a gNB 100 and a UE 200. FIG. 11 is a diagram illustrating an example of the configuration of a vehicle 2001.

[0014] Hereinafter, embodiments will be described with reference to the drawings. Note that the same or similar reference numerals are used to designate the same functions or configurations, and descriptions thereof will be omitted as appropriate.

[0015] (1) Overall Schematic Configuration of Wireless Communication System Fig. 1 is an overall schematic configuration diagram of a wireless communication system 10 according to this embodiment. The wireless communication system 10 is a wireless communication system conforming to 5G New Radio (NR) and includes a Next Generation-Radio Access Network 20 (hereinafter, NG-RAN 20) and a terminal 200 (User Equipment 200, hereinafter, UE 200).

[0016] The wireless communication system 10 may be a wireless communication system conforming to a method called Beyond 5G, 5G Evolution, or 6G, or may include a wireless communication system conforming to a method called Long Term Evolution (LTE) or 4G. The wireless communication system 10 may support functions related to the Industrial Internet of Things (IIoT) and Ultra-Reliable and Low Latency Communications (URLLC).

[0017] The NG-RAN 20 includes a radio base station 100 (hereinafter, gNB 100). Note that the specific configuration of the radio communication system 10, including the number of gNBs (or eNBs, etc.) and UEs, is not limited to the example shown in FIG. 1 .

[0018] The gNB 100 may also employ a fronthaul (FH) interface defined by the Open Radio Access Network Alliance (O-RAN). The gNB 100 may include an O-RAN Distributed Unit (O-DU) and an O-RAN Radio Unit (O-RU). The gNB 100 can function as a type of NG-RAN node.

[0019] The NG-RAN 20 actually includes multiple NG-RAN nodes, specifically, gNBs (or ng-eNBs), and is connected to a 5G core network (5GC, not shown). The NG-RAN 20 and the 5GC may be simply referred to as a "network." The 5GC may introduce the concept of CUPS (Control and User Plane Separation), which clearly separates the functions of the user plane and the control plane.

[0020] The gNB100 is a radio base station conforming to NR, and performs radio communication conforming to NR with the UE200. The gNB100 may be configured to include a CU (Central Unit) and a DU (Distributed Unit), and the DU may be separated from the CU and installed in a different geographical location. One or more DUs may be connected to the CU. The gNB100 (gNB-CU) may be connected to each other via an Xn interface, and the CU and DU may be connected to each other via an F1 interface (such as an F1-AP). In this embodiment, the CU may be called a communication device or a central device. The DU may be called a distributed device.

[0021] The gNB100 and UE200 are capable of supporting Massive MIMO, which generates more directional beams by controlling radio signals transmitted from multiple antenna elements; Carrier Aggregation (CA), which aggregates and uses multiple component carriers (CCs); and Dual Connectivity (DC), which enables simultaneous communication between the UE and multiple NG-RAN nodes.

[0022] The type of DC may be Multi-RAT Dual Connectivity (MR-DC) that uses multiple radio access technologies, or NR-NR Dual Connectivity (NR-DC) that uses only NR. For example, one gNB may constitute a master node (MN), and one or more other gNBs may constitute secondary nodes (SNs).

[0023] In the wireless communication system 10, not only mobility control of the UE 200 in layer 3 (which may be called L3 Mobility) but also mobility control in layer 1 and / or layer 2 (L1 / L2 Mobility) may be applied. L1 / L2 Mobility may be called LTM, and the name LTM will be mainly used hereinafter.

[0024] L3 Mobility may be interpreted as mobility control at the Radio Resource Control layer (RRC), while L1 / L2 Mobility may be interpreted as mobility control at the Physical layer (PHY), Medium Access Control layer (MAC), Radio Link Control layer (RLC), and Packet Data Convergence Protocol layer (PDCP) (mobility control by lower layers).

[0025] LTM may include network-triggered LTM and UE-triggered LTM (Conditional LTM, UE-triggered LTM).

[0026] In addition, in Conditional LTM (which may also be called UE triggered LTM or UE based LTM), like Conditional Handover (CHO), after the radio base station (gNB) receives a specific execution condition, the UE monitors the status according to the execution condition and executes LTM if the execution condition is satisfied.

[0027] Note that the LTM may include LTM fast failure recovery. LTM fast failure recovery is a mechanism in which, in the event of an LTM failure, the UE 200 performs cell selection, and if the selected cell is an LTM candidate cell, the UE 200 directly applies the configuration of the candidate cell without transmitting an RRC Reestablishment Request to the gNB 100.

[0028] In the wireless communication system 10, handover (HO) without a random access procedure may be applied in LTM. Specifically, the UE 200 can perform RACH-less HO, which is HO without using a random access channel (RACH). RACH-less HO may also be referred to as RACH-less LTM.

[0029] In RACH less HO, the UE 200 can calculate a timing advance (TA) by using the time difference between the reception timing of a signal to be measured (e.g., SSB (Synchronization Signal) / PBCH (Physical Broadcast CHannel) Block) between a source cell (which may be interpreted as a serving cell) at the transition source (handover source) and a target cell (handover destination) at the transition destination (handover destination) (UE based TA measurement). Such a TA may be referred to as a UE measured TA, for example.

[0030] In addition, in the case of RACH-less HO, an uplink grant (UL Grant) that allows the UE 200 to transmit an RRC message (RRC Reconfiguration Complete) after HO completion may be configured in advance. Such an UL Grant that is also applicable to RACH-less HO may be deemed invalid if certain conditions are met.

[0031] In the case of RACH less HO, a random access response (RAR) from the gNB to the UE is omitted, so the UE 200 cannot know the timing adjustment value to be applied in the target cell. Therefore, in the wireless communication system 10, a method (early TA acquisition) in which the target cell (which may also be called a target gNB, a candidate cell, etc.) acquires a TA for its own cell in advance may be applied. The TA acquired by the target cell through early TA acquisition is notified to the UE by a Cell Switch Command MAC-CE. In the early TA acquisition, early synchronization specified in 3GPP TS38.300 may be executed.

[0032] In addition, in the wireless communication system 10, in the case of LTM, for the random access channel (PRACH: Physical Random Access Channel), a random access preamble is transmitted in response to an instruction from the PDCCH (Physical Downlink Control Channel), and a PDCCH ordered RACH without RAR, in which the RAR can be omitted, and a PDCCH ordered RACH with RAR, in which the RAR is transmitted from the target cell without omitting the RAR, may be executed.

[0033] RACH less HO (early TA acquisition) is described in 3GPP TS38.401, Chapter 8.2.1.5, etc. Also, PDCCH ordered RACH without RAR is described in 3GPP TS38.300, Chapter 9.2.3.5.2, etc.

[0034] In a broad sense, the mobility of UE200 may mean the ease of movement and maneuverability of UE200, but in this embodiment, it may also mean minimizing call drops, radio link (including beam) failures, unnecessary handovers, ping-pong states, etc.

[0035] Figure 2 shows an example of control by LTM (L1 / L2 mobility). As shown in Figure 2, MAC included in a lower layer (Layer 1 / Layer 2), rather than RRC included in Layer 3, can perform measurement reporting, handover (HO) decision from a source cell to a target cell (which may include candidates), and timer management for determining whether HO is successful.

[0036] The MAC may report information related to the measurement report, the HO decision, etc. to a higher layer (RRC). The RRC may manage the state of radio resources accompanying the cell transition of the UE 200 based on the report.

[0037] The UE 200 transmits a measurement report (hereinafter, referred to as a Measurement report) including reception qualities for cells including a serving cell and neighboring cells to the network. The procedure by which the UE 200 transmits the Measurement report may be referred to as Measurement reporting. The reception qualities for the cells may include reception qualities of beams from the cells, or may include reception qualities of cells based on beams from the cells.

[0038] The UE 200 may periodically perform measurement reporting. The UE 200 may perform measurement reporting for each event. An entering condition for starting measurement reporting and a leaving condition for terminating measurement reporting may be defined for each event. The entering condition may be interpreted as a condition for determining whether or not to include a measurement report target, and the leaving condition may be interpreted as a condition for determining whether or not to exclude a measurement report target. At least one of the entering condition and the leaving condition may be applied as an execution condition in UE triggered LTM.

[0039] In this embodiment, the channels include a control channel and a data channel, such as a physical downlink control channel (PDCCH), a physical uplink control channel (PUCCH), a physical random access channel (PRACH), and a physical broadcast channel (PBCH).

[0040] The data channels include a physical downlink shared channel (PDSCH) and a physical uplink shared channel (PUSCH).

[0041] The reference signal includes a Demodulation Reference Signal (DMRS), a Sounding Reference Signal (SRS), a Phase Tracking Reference Signal (PTRS), and a Channel State Information-Reference Signal (CSI-RS), and the signal includes a channel and a reference signal. Furthermore, the data may refer to data transmitted via a data channel.

[0042] (2) Functional Block Configuration of Wireless Communication System Next, the functional block configuration of the wireless communication system 10 will be described. Specifically, the functional block configuration of the gNB 100 and the UE 200 will be described. Fig. 3 is a functional block configuration diagram of the gNB 100. Fig. 4 is a functional block configuration diagram of the UE 200.

[0043] (2.1) gNB100 As shown in FIG. 3, the gNB100 includes a radio communication unit 110, a handover processing unit 120, an RA procedure management unit 130, and a control unit 140.

[0044] The wireless communication unit 110 transmits downlink signals (DL signals) conforming to NR, and also receives uplink signals (UL signals) conforming to NR.

[0045] The handover processing unit 120 executes handover of the UE 200. Specifically, the handover processing unit 120 executes handover from a serving cell (source cell) of the UE 200 to another nearby cell (target cell). In particular, in this embodiment, the handover processing unit 120 may execute handover in accordance with L1 / L2 mobility (LTM). Note that the source cell and the target cell may also be referred to as a source radio base station (gNB) and a target radio base station (gNB).

[0046] Handover (HO) may also be called cell transition, cell selection, or cell reselection. Handover may be cell-based, but may also involve changing (switching) some of the beams to another cell.

[0047] The serving cell may be simply interpreted as the cell to which the UE 200 is connected, or more precisely, in the case of an RRC_CONNECTED UE without carrier aggregation (CA), there is only one serving cell that constitutes the primary cell. In the case of an RRC_CONNECTED UE configured with CA, the serving cell may be interpreted as indicating a set of one or more cells including the primary cell and all secondary cells.

[0048] The handover may also include a conditional handover (CHO) and / or a dual active protocol stack (DAPS) handover. CHO can execute a handover initiated by the UE 200 when a specific execution condition is met. If CHO is not applicable, a normal handover may be executed (which may be called CHO recovery). In CHO recovery, the UE 200 executes cell selection after a CHO failure. If a CHO candidate cell is selected, the UE 200 can directly apply a conditional RRC reconfiguration of the selected cell to reconnect without transmitting an RRC Restablishment Request to the candidate target cell.

[0049] The RA procedure management unit 130 manages operations related to a random access procedure (RA procedure) with the UE 200. The RA procedure management unit 130 also sets a timing advance (TA) value and the like.

[0050] Specifically, the RA procedure management unit 130 may manage the RACH (RA procedure method applied to the UE 200. More specifically, the RA procedure management unit 130 may apply either a PDCCH ordered RACH without RAR or a PDCCH ordered RACH with RAR to the UE 200.

[0051] In this embodiment, the RA procedure management unit 130 may receive a random access preamble transmitted from the UE 200. The RA procedure management unit 130 can set a TA value to be applied to the own cell, etc. (a cell or beam formed by the gNB 100).

[0052] The control unit 140 controls each functional block constituting the gNB 100. In particular, in this embodiment, the control unit 140 can perform mobility control with the UE 200. Specifically, the control unit 140 can perform not only mobility control according to L3 Mobility but also mobility control according to L1 / L2 Mobility (LTM).

[0053] In addition, the control unit 140 can perform control as a CU (source side or target side) or a DU (source side or target side) in a gNB100 having a CU-DU configuration.

[0054] In this embodiment, the control unit 140 may perform early acquisition of a timing adjustment value of a target cell with the UE 200 that performs cell transition to the target cell without performing a random access procedure. Specifically, the control unit 140 may perform early TA acquisition with the UE 200 that performs RACH less HO.

[0055] Furthermore, the control unit 140 may determine whether to activate or deactivate an execution condition for the UE 200 that executes cell transfer regardless of an instruction from the network when an execution condition is satisfied, such as Conditional LTM (UE triggered LTM).

[0056] (2.2) UE 200 As shown in FIG. 4, the UE 200 includes a radio communication unit 210, an RA execution unit 220, a handover execution unit 230, and a control unit 240.

[0057] The wireless communication unit 210 transmits an uplink signal (UL signal) conforming to NR. The wireless communication unit 210 also receives an uplink signal (DL signal) conforming to NR.

[0058] The RA execution unit 220 executes a random access procedure (RA procedure) with the gNB 100. Specifically, the RA execution unit 220 may execute the RA procedure in accordance with a PDCCH ordered RACH without RAR or a PDCCH ordered RACH with RAR.

[0059] More specifically, the RA execution unit 220 may transmit a random access preamble to the network (gNB) based on a command via a downlink control channel (PDCCH). In this embodiment, the RA execution unit 220 may constitute a transmission unit. The transmission of the random access preamble may be premised on the reception of a random access response (RAR). Note that, here, the RACH (which may be read as an RA procedure) may be initiated by the PDCCH, but other physical channels in the downlink direction may be used instead of the PDCCH.

[0060] The RA execution unit 220 may execute timing advance (TA) acquisition. Specifically, the RA execution unit 220 may acquire TA through UE-based TA measurement or PDCCH-ordered RACH (PDCCH-ordered RACH without RAR, PDCCH-ordered RACH with RAR).

[0061] The RA executor 220 may receive a command, a Media Access Control element (MAC CE) or a Radio Resource Control layer (RRC) message including an instruction to start a timer for a Timing Adjustment (TA). In this embodiment, the RA executor 220 may constitute a receiver.

[0062] The timer for TA may be, for example, a timeAlignmentTimer that measures the validity period of TA. The timeAlignmentTimer may be a conventional timeAlignmentTimer or a new timeAlignmentTimer defined for PDCCH-ordered RACH. The command including an instruction to start the timer for TA may refer to the PDCCH used for PDCCH-ordered RACH.

[0063] The RA executor 220 may receive a command (PDCCH), MAC CE or RRC message containing the validity period of the TA.

[0064] The RA execution unit 220 may also transmit a random access report (RA report) regarding the RA procedure to the network. For example, the RA report may include identification information of a candidate cell to which LTM is to be transferred, an index of a frequency band used and a beam used, the number of times a random access preamble has been transmitted, and information indicating that the random access procedure has failed.

[0065] The RA execution unit 220 may transmit capability information (UE Capability Information) indicating capabilities related to transmission of a random access preamble to the network. In this embodiment, the RA execution unit 220 may constitute a transmission unit that transmits the capability information. Specifically, the RA execution unit 220 may transmit UE Capability Information indicating capabilities related to acquisition of a timing advance (TA) to be applied to a candidate cell for handover by LTM.

[0066] For example, the RA execution unit 220 may transmit UE Capability Information including support for the validity period of the acquired TA, support for the timeAlignmentTimer used for the PDCCH-ordered RACH, and whether or not the TAs are supported.

[0067] The handover execution unit 230 executes handover of the UE 200. Specifically, the handover execution unit 230 may execute handover to a transfer destination cell (NG-RAN node) based on control by the gNB 100.

[0068] The handover execution unit 230 can also execute processes related to normal handover (legacy handover), handover according to LTM (L1 / L2 Mobility), conditional handover (CHO), and DAPS handover. The handover execution unit 230 can also support RACH less HO (RACH less LTM).

[0069] Furthermore, the handover execution unit 230 may execute early TA acquisition in order to execute RACH less HO.

[0070] The handover execution unit 230 may transition to the candidate cell when an execution condition is satisfied. The execution condition may be determined based on the quality of the reference signal (RS), specifically, the value of the reference signal received power (RSRP), the reference signal received quality (RSRQ), or the signal-to-interference plus noise power ratio (SINR).

[0071] As described above, handover may be interpreted as transition, cell transition, cell selection, etc. Specifically, the handover execution unit 230 may execute handover based on LTM based on at least one command of layer 1 and / or layer 2.

[0072] The type of the command is not particularly limited, and may be, for example, an L1 / L2 Mobility command (e.g., Cell Switch Command MAC-CE). The L1 / L2 Mobility command may be replaced with another command of the RRC layer.

[0073] The control unit 240 controls each functional block constituting the UE 200. Specifically, the control unit 240 can execute control relating to handover of the UE 200.

[0074] The control unit 240 can also perform L1 / L2 Mobility (LTM), i.e., mobility control of at least one of layer 1 and layer 2. Mobility control by L1 / L2 Mobility may include quality measurement of service areas and neighboring cells in layer 1 or layer 2, setting of destination candidate cells, cell reselection (transition), handover, etc. In this way, the control unit 240 can perform handover in accordance with mobility control by a lower layer.

[0075] Specifically, the control unit 240 may acquire a timing adjustment (TA) to be applied to a candidate cell to which a transition is to be made by a lower layer terminal-driven mobility control (LTM) using a PDCCH command (PDCCH ordered RACH), and start (activate) a timer (timeAlignmentTimer) that measures the validity period of the timing adjustment.

[0076] More specifically, the control unit 240 may control the RA execution unit 220 to cause the RA execution unit 220 to acquire a timing adjustment (TA) to be applied to an LTM candidate cell. When the TA is acquired, the control unit 240 may start the timeAlignmentTimer. The start timing of the timeAlignmentTimer may be simultaneous with the acquisition of the TA, or after a certain time lag has been provided. The setting value of the timeAlignmentTimer (the validity period of the TA) may be specified in advance according to the 3GPP specifications, or may be dynamically set by the network or dynamically set according to the radio quality.

[0077] The control unit 240 may start the timeAlignmentTimer when an execution condition for transition to a candidate cell is set and a timing adjustment (TA) is acquired by a command via a PDCCH (PDCCH ordered RACH). That is, the control unit 240 may apply the timeAlignmentTimer on the condition that the execution condition is set.

[0078] The control unit 240 may apply the same timeAlignmentTimer to a group of multiple Timing Adjustments (TAs) that fall within a specific range. Specifically, the control unit 240 may set the same timeAlignmentTimer (i.e., the same TA validity period) to multiple cells that have the same or similar TA values ​​and whose TA values ​​fall within a specific range.

[0079] (3) Operation of the Wireless Communication System Next, a description will be given of the operation of the wireless communication system 10. Specifically, a description will be given of an operation example in which PDCCH ordered RACH with RAR is applied in Conditional LTM.

[0080] (3.1) Assumptions and Issues As described above, the wireless communication system 10 may support PDCCH ordered RACH without RAR and PDCCH ordered RACH with RAR in relation to the random access procedure.

[0081] Fig. 5 shows an example of a RACH sequence according to a PDCCH ordered RACH without RAR, and Fig. 6 shows an example of a RACH sequence according to a PDCCH ordered RACH with RAR.

[0082] As shown in Fig. 5 , PDCCH ordered RACH without RAR is specified in 3GPP Release-18, while PDCCH ordered RACH with RAR is being considered in 3GPP Release-19, as shown in Fig. 6 .

[0083] In PDCCH ordered RACH without RAR, the RA procedure may be initiated by a command via PDCCH, and the UE may obtain the TA value applied to the target cell by an LTM cell switch command (Cell Switch Command MAC-CE) after sending a random access preamble (RACH preamble) to the target gNB. In PDCCH ordered RACH without RAR, the random access response (RAR) can be omitted.

[0084] On the other hand, in a PDCCH ordered RACH with RAR, the UE may obtain the TA value applied to the target cell through RAR.

[0085] In addition, in LTM, the TA can be obtained by the PDCCH-ordered RACH described above, or the UE can obtain the TA by directly measuring the TA (which may be called UE-based TA measurement).

[0086] In the case of UE-based TA measurement, the UE ensures the validity of the TA value by the timeAlignmentTimer (which may also be called the TA timer). On the other hand, in the case of PDCCH-ordered RACH, the management of the validity of the TA value may be ensured by the network implementation. In other words, the UE does not need to be equipped with the timeAlignmentTimer.

[0087] FIG. 7 is an explanatory diagram of the relationship between the satisfaction of the execution condition in Conditional LTM and the LTM cell switch.

[0088] As shown in Fig. 7, the UE monitors the execution condition in the Conditional LTM. If the execution condition is satisfied, the UE performs a cell switch (which may be interpreted as a handover) to a candidate cell. The cell switch is performed at the initiative of the UE.

[0089] In addition, in the case of Conditional LTM, the following methods can be considered for early TA acquisition.

[0090] ・UE based TA measurement ・PDCCH ordered RACH without RAR ・PDCCH ordered RACH with RAR In the case of PDCCH ordered RACH (PDCCH ordered RACH without RAR, PDCCH ordered RACH with RAR), it may take some time for the execution condition to be satisfied after TA acquisition, and the TA value may become invalid.

[0091] Furthermore, when TA is acquired by PDCCH-ordered RACH, the UE needs to manage the acquired TA, which may cause confusion if there is no clear instruction from the network.

[0092] An example of an operation that can solve this problem will be described below.

[0093] (3.2) Operational Example Figure 8 shows an application example of the timeAlignmentTimer according to the operational example. After acquiring TA via PDCCH-ordered RACH in a candidate cell (LTM candidate cell), the UE may start (or restart, the same applies below) the timeAlignmentTimer. Note that the LTM in this case may be a Conditional LTM (UE-triggered LTM).

[0094] The UE may start the timeAlignmentTimer after the execution condition of Conditional LTM is configured and the UE acquires TA by the PDCCH ordered RACH in the LTM candidate cell.

[0095] The PDCCH of the PDCCH ordered RACH, another PDCCH from the network, MAC CE, or RRC message may include an instruction for the UE to start the timeAlignmentTimer after acquiring the TA.

[0096] In addition, the PDCCH of the PDCCH ordered RACH, another PDCCH from the network, MAC CE, or RRC message may include an instruction for the UE to manage the validity period of the TA using the timeAlignmentTimer.

[0097] The timeAlignmentTimer may be set for each LTM candidate cell. Multiple LTM candidate cells with the same or similar TA values ​​may be grouped, and one timeAlignmentTimer may be set for the group, and the TA validity period applied to the group may be managed collectively by the timeAlignmentTimer. Furthermore, multiple LTM candidate cells with the same or similar TA values ​​may belong to the same TAG (TA Group).

[0098] The UE may consider the TA value invalid when the timeAlignmentTimer expires. The UE may also perform the following actions when the timeAlignmentTimer expires:

[0099] ・flush all HARQ buffers for all Serving Cells; ・notify RRC to release PUCCH for all Serving Cells, if configured; ・notify RRC to release SRS for all Serving Cells, if configured; ・clear any configured downlink assignments and configured uplink grants; ・clear any PUSCH resource for semi-persistent CSI reporting; ・consider all running timeAlignmentTimers as expired; ・maintain N TA (defined in TS 38.211 [8]) of all TAGs.

[0100] (3.3) UE Capability Figure 9 shows an example of a transmission sequence of UE capability information. Regarding TA acquisition by PDCCH ordered RACH, a UE may report the presence or absence of the following capabilities (UE capability information) to the network. The UE capability information may be defined for each UE, frequency range (FR), frequency channel (FC), etc. Furthermore, RRC signaling and configuration for reporting the UE capability information may be defined.

[0101] Ability to acquire a TA in an LTM candidate cell via a PDCCH ordered RACH and manage TA validity using the timeAlignmentTimer; Ability to manage the validity of the TA value of an LTM candidate cell on the UE side; Ability to manage the validity of the TA values ​​of multiple LTM candidate cells on the UE side; Ability to manage the validity of the TA value of an LTM candidate cell on the UE side using the timeAlignmentTimer; Ability to manage the validity of the TA values ​​of multiple LTM candidate cells on the UE side using the timeAlignmentTimer. According to the above-described operational example, even when a PDCCH ordered RACH is applied, the UE can manage the validity period of the acquired TA using the timeAlignmentTimer. Therefore, the UE can operate appropriately using the acquired TA even when early TA acquisition is performed in Conditional LTM.

[0102] (4) Other Embodiments The contents of the present proposal have been described above in accordance with the examples, but it will be obvious to those skilled in the art that the present proposal is not limited to these descriptions and that various modifications and improvements are possible.

[0103] Although the embodiments have been described above, it will be obvious to those skilled in the art that the present invention is not limited to the description of the embodiments and that various modifications and improvements are possible.

[0104] For example, in the above-described embodiment, the names PDCCH ordered RACH without RAR and PDCCH ordered RACH with RAR are used, but these names may be provisional names, and other names may be used as long as the RACH is initiated by the PDCCH.

[0105] In the above description, configure, activate, update, indicate, enable, specify, and select may be interchangeable. Similarly, link, associate, correspond, and map may be interchangeable, and allocate, assign, monitor, and map may be interchangeable.

[0106] Furthermore, specific, dedicated, UE-specific, and UE-dedicated may be interchangeable. Similarly, common, shared, group-common, UE-common, and UE-shared may be interchangeable.

[0107] In this disclosure, terms such as "precoding," "precoder," "weight (precoding weight)," "Quasi-Co-Location (QCL)," "Transmission Configuration Indication state (TCI state)," "spatial relation," "spatial domain filter," "transmit power," "phase rotation," "antenna port," "antenna port group," "layer," "number of layers," "rank," "resource," "resource set," "resource group," "beam," "beam width," "beam angle," "antenna," "antenna element," "panel," etc. may be used interchangeably.

[0108] Furthermore, the block diagrams (FIGS. 3 and 4) used to explain the above-described embodiments show functional blocks. These functional blocks (components) are realized by any combination of hardware and / or software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are connected directly or indirectly (e.g., wired, wireless, etc.) and these multiple devices. The functional block may also be realized by combining software with the single device or multiple devices.

[0109] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on how each is implemented.

[0110] Furthermore, the above-described gNB100 and UE200 (the devices) may function as a computer that performs processing of the wireless communication method of the present disclosure. Figure 10 is a diagram showing an example of the hardware configuration of the devices. As shown in Figure 10, the devices may be configured as a computer including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0111] In the following description, the term "apparatus" can be interpreted as a circuit, a device, a unit, etc. The hardware configuration of the apparatus may be configured to include one or more of the apparatuses shown in the drawings, or may be configured to exclude some of the apparatuses.

[0112] Each functional block of the device (see FIGS. 3 and 4) is realized by any hardware element of the computer device or a combination of the hardware elements.

[0113] In addition, each function of the device is realized by loading specified software (programs) onto hardware such as processor 1001 and memory 1002, causing processor 1001 to perform calculations, control communication via communication device 1004, and control at least one of reading and writing data in memory 1002 and storage 1003.

[0114] The processor 1001 controls the entire computer by running, for example, an operating system, and may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control unit, an arithmetic unit, and registers.

[0115] The processor 1001 also reads programs (program codes), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002 and executes various processes in accordance with these. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. Furthermore, the various processes described above may be executed by a single processor 1001, or may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may be transmitted from a network via a telecommunications line.

[0116] The memory 1002 is a computer-readable recording medium and may be configured by at least one of, for example, a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), etc. The memory 1002 may also be called a register, a cache, a main memory (primary storage device), etc. The memory 1002 may store a program (program code), a software module, etc., capable of executing a method according to an embodiment of the present disclosure.

[0117] Storage 1003 is a computer-readable recording medium, and may be, for example, at least one of an optical disk such as a Compact Disc ROM (CD-ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray disc), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy disk, a magnetic strip, etc. Storage 1003 may also be referred to as an auxiliary storage device. The above-mentioned recording medium may be, for example, a database, a server, or other suitable medium including at least one of memory 1002 and storage 1003.

[0118] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also called, for example, a network device, a network controller, a network card, or a communication module.

[0119] The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize, for example, at least one of Frequency Division Duplex (FDD) and Time Division Duplex (TDD).

[0120] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that outputs to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0121] Furthermore, each device such as the processor 1001 and the memory 1002 is connected to a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0122] Furthermore, the device may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0123] Furthermore, the notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., RRC signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB))), other signals, or a combination thereof. Furthermore, the RRC signaling may be referred to as an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0124] Each aspect / embodiment described in the present disclosure may be applied to at least one of a system using Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, a 4th generation mobile communication system (4G), a 5th generation mobile communication system (5G), a 6th generation mobile communication system (6G), an xth generation mobile communication system (xG) (where x is, for example, an integer or a decimal), Future Radio Access (FRA), New Radio (NR), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), or other suitable system, and a next-generation system extended based on these. Furthermore, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A with 5G) may also be applied.

[0125] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be changed unless it is consistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0126] In the present disclosure, a specific operation described as being performed by a base station may also be performed by its upper node in some cases. In a network consisting of one or more network nodes having a base station, it is clear that various operations performed for communication with a terminal may be performed by at least one of the base station and another network node other than the base station (e.g., MME or S-GW, etc., but are not limited to these). Although the above example illustrates a case where there is one other network node other than the base station, a combination of multiple other network nodes (e.g., MME and S-GW) may also be used.

[0127] Information, signals (information, etc.) may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer), or may be input and output via multiple network nodes.

[0128] The input and output information may be stored in a specific location (for example, a memory) or may be managed using a management table. The input and output information may be overwritten, updated, or added to. The output information may be deleted. The input information may be transmitted to another device.

[0129] The determination may be made based on a value represented by one bit (0 or 1), a Boolean value (true or false), or a numerical comparison (e.g., comparison with a predetermined value).

[0130] The aspects / embodiments described in this disclosure may be used alone, in combination, or switched depending on the implementation. Notification of predetermined information (e.g., notification that "X is true") is not limited to explicit notification, but may be implicit (e.g., not notifying the predetermined information).

[0131] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0132] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0133] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0134] Note that terms described in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Furthermore, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0135] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0136] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by an index.

[0137] The names used for the above-described parameters are not intended to be limiting in any way. Furthermore, the mathematical expressions using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any way.

[0138] In this disclosure, terms such as "base station (BS)," "radio base station," "fixed station," "NodeB," "eNodeB (eNB)," "gNodeB (gNB)," "access point," "transmission point," "reception point," "transmission / reception point," "cell," "sector," "cell group," "carrier," and "component carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0139] A base station can accommodate one or more (e.g., three) cells (also called sectors). When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be divided into multiple smaller areas, and each smaller area can be provided with communication services by a base station subsystem (e.g., a small indoor base station (Remote Radio Head: RRH)).

[0140] The terms "cell" or "sector" refer to part or all of the coverage area of ​​a base station and / or base station subsystem that provides communication services within that coverage area.

[0141] In the present disclosure, the base station transmitting information to a terminal may be interpreted as the base station instructing the terminal to control or operate based on the information.

[0142] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0143] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0144] At least one of the base station and the mobile station may be referred to as a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a mobile object, the mobile object itself, etc. The mobile object refers to a movable object, and may move at any speed. Naturally, this also includes cases where the mobile object is stationary. Examples of the mobile object include, but are not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcars, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones (registered trademark), multicopters, quadcopters, balloons, and objects mounted thereon. The mobile object may also be a mobile object that moves autonomously based on an operational command. It may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may be a device that does not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

[0145] Furthermore, a base station in the present disclosure may be read as a mobile station (user terminal, the same applies hereinafter). For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a mobile station is replaced with communication between multiple mobile stations (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the mobile station may be configured to have the functions of a base station. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel (or sidelink).

[0146] Similarly, a mobile station in the present disclosure may be interpreted as a base station, in which case the base station may have the functions of a mobile station.

[0147] A radio frame may be composed of one or more frames in the time domain. Each of the one or more frames in the time domain may be called a subframe. A subframe may further be composed of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0148] Numerology may be communication parameters that apply to the transmission and / or reception of a signal or channel, such as subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, specific filtering operations performed by the transceiver in the frequency domain, and specific windowing operations performed by the transceiver in the time domain.

[0149] A slot may consist of one or more symbols in the time domain (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol, a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol, etc.) A slot may be a numerology-based time unit.

[0150] A slot may include multiple minislots. Each minislot may consist of one or more symbols in the time domain. A minislot may also be called a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (or PUSCH) mapping type B.

[0151] The radio frame, subframe, slot, minislot, and symbol all represent time units for transmitting signals, and may be referred to by other names corresponding to the radio frame, subframe, slot, minislot, and symbol.

[0152] For example, one subframe may be referred to as a transmission time interval (TTI), multiple consecutive subframes may be referred to as a TTI, or one slot or one minislot may be referred to as a TTI. That is, at least one of the subframe and the TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (e.g., 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc., instead of a subframe.

[0153] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station schedules each user terminal to allocate radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) in TTI units. Note that the definition of TTI is not limited to this.

[0154] The TTI may be a transmission time unit for a channel-encoded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) to which a transport block, a code block, a code word, etc. is actually mapped may be shorter than the TTI.

[0155] In addition, when one slot or one minislot is called a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit for scheduling, and the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0156] A TTI having a time length of 1 ms may be referred to as a regular TTI (TTI in LTE Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be referred to as a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0157] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length of more than 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and equal to or greater than 1 ms.

[0158] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of numerology, for example, 12. The number of subcarriers included in an RB may be determined based on numerology.

[0159] The time domain of an RB may include one or more symbols and may have a length of one slot, one minislot, one subframe, or one TTI, each of which may consist of one or more resource blocks.

[0160] Note that one or more RBs may also be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0161] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0162] A Bandwidth Part (BWP) (which may also be referred to as a fractional bandwidth) may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by their index relative to a common reference point of the carrier. PRBs may be defined in a given BWP and numbered within that BWP.

[0163] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). One or more BWPs may be configured for a UE within one carrier.

[0164] At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a predetermined signal / channel outside the active BWP. Note that the terms "cell," "carrier," etc. in this disclosure may be read as "BWP."

[0165] The above-described structures of the radio frame, subframe, slot, minislot, and symbol are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, and other configurations may be changed in various ways.

[0166] The terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using one or more wires, cables, and / or printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0167] The reference signal may also be abbreviated as Reference Signal (RS) and may be called a pilot depending on the applicable standard.

[0168] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0169] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0170] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed therein or that the first element must precede the second element in some way.

[0171] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Furthermore, when the term "or" is used in this disclosure, it is not intended to be an exclusive or.

[0172] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0173] As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (e.g., searching in a table, database, or other data structure), ascertaining, and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), and the like. Furthermore, "judgment" and "decision" can include regarding resolving, selecting, choosing, establishing, comparing, etc. as having been "judged" or "decided." In other words, "judgment" and "decision" can include regarding some action as having been "judged" or "decided." Furthermore, "judgment (decision)" can be interpreted as "assuming," "expecting," "considering," etc.

[0174] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0175] 11 shows an example of the configuration of a vehicle 2001. As shown in Fig. 11, the vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013.

[0176] The drive unit 2002 is composed of, for example, an engine, a motor, or a hybrid of an engine and a motor. The steering unit 2003 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels and the rear wheels based on the operation of the steering wheel operated by the user. The electronic control unit 2010 is composed of a microprocessor 2031, memory (ROM, RAM) 2032, and a communication port (IO port) 2033. Signals from various sensors 2021 to 2027 provided in the vehicle are input to the electronic control unit 2010. The electronic control unit 2010 may also be called an ECU (Electronic Control Unit).

[0177] The signals from the various sensors 2021 to 2028 include a current signal from a current sensor 2021 that senses the current of the motor, a rotation speed signal of the front and rear wheels obtained by a rotation speed sensor 2022, an air pressure signal of the front and rear wheels obtained by an air pressure sensor 2023, a vehicle speed signal obtained by a vehicle speed sensor 2024, an acceleration signal obtained by an acceleration sensor 2025, an accelerator pedal depression amount signal obtained by an accelerator pedal sensor 2029, a brake pedal depression amount signal obtained by a brake pedal sensor 2026, a shift lever operation signal obtained by a shift lever sensor 2027, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. obtained by an object detection sensor 2028.

[0178] The information service unit 2012 is composed of various devices, such as a car navigation system, an audio system, speakers, a television, and a radio, for providing (outputting) various types of information, such as driving information, traffic information, and entertainment information, and one or more ECUs for controlling these devices. The information service unit 2012 uses information acquired from external devices via the communication module 2013, etc., to provide various types of multimedia information and multimedia services to the occupants of the vehicle 1.

[0179] The information service unit 2012 may include input devices (e.g., keyboards, mice, microphones, switches, buttons, sensors, touch panels, etc.) that accept input from the outside, and may also include output devices (e.g., displays, speakers, LED lamps, touch panels, etc.) that output to the outside.

[0180] The driving assistance system unit 2030 is composed of various devices that provide functions for preventing accidents and reducing the driver's driving burden, such as millimeter-wave radar, LiDAR (Light Detection and Ranging), cameras, positioning locators (e.g., GNSS, etc.), map information (e.g., high-definition (HD) maps, autonomous vehicle (AV) maps, etc.), gyro systems (e.g., IMU (Inertial Measurement Unit), INS (Inertial Navigation System), etc.), AI (Artificial Intelligence) chips, and AI processors, as well as one or more ECUs that control these devices. The driving assistance system unit 2030 also transmits and receives various information via the communication module 2013 to realize driving assistance functions or autonomous driving functions.

[0181] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 1 via the communication port. For example, the communication module 2013 transmits and receives data via the communication port 2033 to and from a driving unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, an axle 2009, a microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021 to 2028, which are provided in the vehicle 2001.

[0182] The communication module 2013 is a communication device that can be controlled by the microprocessor 2031 of the electronic control unit 2010 and can communicate with an external device. For example, it transmits and receives various information to and from the external device via wireless communication. The communication module 2013 may be located either inside or outside the electronic control unit 2010. The external device may be, for example, a base station, a mobile station, or the like.

[0183] The communication module 2013 may transmit at least one of signals from the above-mentioned various sensors 2021 to 2028 input to the electronic control unit 2010, information obtained based on the signals, and information based on input from the outside (user) obtained via the information service unit 2012 to an external device via wireless communication. The electronic control unit 2010, the various sensors 2021 to 2028, the information service unit 2012, etc. may be referred to as input units that accept input. For example, the PUSCH transmitted by the communication module 2013 may include information based on the above-mentioned input.

[0184] The communication module 2013 receives various information (traffic information, traffic signal information, vehicle-to-vehicle information, etc.) transmitted from external devices and displays it on an information service unit 2012 provided in the vehicle. The information service unit 2012 may also be called an output unit that outputs information (for example, outputs information to a device such as a display or speaker based on the PDSCH (or data / information decoded from the PDSCH) received by the communication module 2013). The communication module 2013 also stores the various information received from external devices in a memory 2032 that can be used by the microprocessor 2031. Based on the information stored in the memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, axles 2009, sensors 2021 to 2028, and the like provided in the vehicle 2001.

[0185] (Additional Note) The above disclosure may be expressed as follows: A first feature is a terminal including: a transmitter that transmits a random access preamble based on a command over a downlink control channel, and a controller that, in a candidate cell to which a terminal is to transition based on terminal-initiated mobility control by a lower layer, acquires a timing adjustment value to be applied to the candidate cell based on the command, and starts a timer that measures a validity period of the timing adjustment value.

[0186] A second feature is the first feature, wherein the control unit starts the timer when an execution condition for transition to the candidate cell is set and the timing adjustment value is obtained by the command.

[0187] A third feature, in the first or second feature, further includes a receiving unit that receives the command, a control element of a medium access control layer, or a message of a radio resource control layer, including an instruction to start the timer.

[0188] A fourth feature is the first to third feature, wherein the receiving unit receives the command, the control element, or the message including the validity period.

[0189] A fifth feature, in any one of the first to fourth features, is that the control unit applies the same timer to a group of a plurality of the timing adjustment values ​​included in a specific range.

[0190] This patent application claims priority based on Japanese Patent Application No. 2024-137770, filed on August 19, 2024, the entire contents of which are incorporated herein by reference.

[0191] 10 Wireless communication system 20 NG-RAN 100 gNB 110 Wireless communication unit 120 Handover processing unit 130 TA setting unit 140 Control unit 200 UE 210 Wireless communication unit 220 Measurement reporting unit 230 Handover execution unit 240 Control unit 1001 Processor 1002 Memory 1003 Storage 1004 Communication device 1005 Input device 1006 Output device 1007 Bus 2001 Vehicle 2002 Drive unit 2003 Steering unit 2004 Accelerator pedal 2005 Brake pedal 2006 Shift lever 2007 Left and right front wheels 2008 Left and right rear wheels 2009 Axle 2010 Electronic control unit 2012 Information service unit 2013 Communication module 2021 Current sensor 2022 RPM sensor 2023 Air pressure sensor 2024 Vehicle speed sensor 2025 Acceleration sensor 2026 Brake pedal sensor 2027 Shift lever sensor 2028 Object detection sensor 2029 Accelerator pedal sensor 2030 Driving assistance system section 2031 Microprocessor 2032 Memory (ROM, RAM) 2033 Communication port

Claims

1. A terminal comprising: a transmitter that transmits a random access preamble based on an instruction via a downlink control channel; and a controller that, in a candidate cell to which a transition is to be made based on terminal-initiated mobility control via a lower layer, acquires a timing adjustment value to be applied to the candidate cell based on the instruction, and starts a timer that measures the validity period of the timing adjustment value.

2. The terminal according to claim 1, wherein the control unit starts the timer when a condition for executing a transition to the candidate cell is set and the timing adjustment value is obtained by the command.

3. The terminal according to claim 1, further comprising a receiver for receiving the command, a control element of a medium access control layer, or a message of a radio resource control layer, including an instruction to start the timer.

4. The terminal according to claim 3, wherein the receiving unit receives the command, the control element, or the message including the validity period.

5. The terminal according to claim 1, wherein the control unit applies the same timer to a group of a plurality of timing adjustment values ​​that fall within a specific range.

6. A wireless communication method in a terminal, comprising: a step of transmitting a random access preamble based on an instruction via a downlink control channel; and a step of obtaining a timing adjustment value to be applied to a candidate cell to which a terminal is to transition based on terminal-initiated mobility control by a lower layer based on the instruction, and starting a timer that measures the validity period of the timing adjustment value.

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